System and method of forming a nanotube mesh structure

ABSTRACT

A system for use in producing a nanotube mesh structure is provided. The system includes a first nanotube collection apparatus including a first substrate configured to collect a plurality of nanotubes substantially aligned in a first orientation on an attachment surface thereof, and a second nanotube collection apparatus including a second substrate configured to collect a plurality of nanotubes substantially aligned in a second orientation on an attachment surface thereof. The first and second nanotube collection apparatuses are configured to combine the pluralities of nanotubes at an interface. The system also includes a first energy source configured to direct energy towards the interface between the pluralities of nanotubes, wherein the energy is configured to join the pluralities of nanotubes to form the nanotube mesh structure.

BACKGROUND

The field of the present disclosure relates generally to nanotubetechnology and, more particularly, to systems and methods of forming ananotube mesh structure.

Carbon nanotubes are small tube-shaped structures fabricated essentiallyfrom single-atom thick sheets of graphene in tubular form. Generally,carbon nanotubes can be classified as either single-wall or multi-wallcarbon nanotubes. Single-wall carbon nanotubes have only one cylindricalgraphitic layer, and multi-wall carbon nanotubes have two or more nestedcylindrical graphitic layers. Carbon nanotubes generally have a diameterless than about 100 nanometers and large aspect ratios such that alength of the nanotube is significantly greater than its diameter. Forexample, the length to diameter ratio of carbon nanotubes may be greaterthan about 1000 to 1. Moreover, carbon nanotubes have been shown toexhibit high strength, unique electrical properties, and to be efficientconductors of heat. Such features make carbon nanotubes advantageous foruse in a variety of mechanical, electrical, and/or thermal applications.

However, the use of carbon nanotubes in practical applications isgenerally limited by the small size of the carbon nanotubes. Recently,several known processes have been established to form carbon nanotubestructures of increasingly large sizes that may be implemented in suchpractical applications. One known process includes dispersing carbonnanotubes in a bath of solution, substantially aligning the carbonnanotubes in the solution, and iteratively collecting the carbonnanotubes on a surface of a substrate passing through the bath ofsolution. The carbon nanotubes are generally iteratively collected indifferent orientations of the substrate. The carbon nanotubesaccumulated on the surface of the substrate are then joined to form acarbon nanotube mesh structure, or “buckypaper.” However, the size ofcarbon nanotube mesh structures formed in such processes is generallylimited by the dimensions of the substrate and/or the bath of solution.

BRIEF DESCRIPTION

In one aspect, a system for use in producing a nanotube mesh structureis provided. The system includes a first nanotube collection apparatusincluding a first substrate configured to collect a plurality ofnanotubes substantially aligned in a first orientation on an attachmentsurface thereof, and a second nanotube collection apparatus including asecond substrate configured to collect a plurality of nanotubessubstantially aligned in a second orientation on an attachment surfacethereof. The first and second nanotube collection apparatuses areconfigured to combine the pluralities of nanotubes at an interface. Thesystem also includes a first energy source configured to direct energytowards the interface between the pluralities of nanotubes, wherein theenergy is configured to join the pluralities of nanotubes to form thenanotube mesh structure.

In another aspect, an apparatus for use in collecting nanotubes isprovided. The apparatus includes a bath of solution including aplurality of nanotubes floating on a surface of the solution, and a feedsystem configured to continuously direct a substrate including anattachment surface past the surface of the solution. The plurality ofnanotubes couple to the attachment surface in a substantially parallelorientation as the feed system directs the attachment surface past thesurface of the solution.

In yet another aspect, a method of forming a nanotube mesh structure isprovided. The method includes continuously directing a substrateincluding an attachment surface past a surface of a bath of solutionincluding a plurality of nanotubes floating on a surface of the solutionsuch that the plurality of nanotubes couple to the attachment surface ina first orientation, combining the plurality of nanotubes in the firstorientation with a plurality of nanotubes in a second orientation, thepluralities of nanotubes combined at an interface defined therebetween,and thermally coupling the pluralities of nanotubes at the interface toform the nanotube mesh structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow diagram of an exemplary aircraft production and servicemethod.

FIG. 2 is a block diagram of an exemplary aircraft.

FIG. 3 is a schematic illustration of an exemplary nanotube meshstructure production system.

FIG. 4 is an enlarged schematic illustration of an exemplary firstnanotube collection apparatus that may be used with the nanotube meshstructure production system shown in FIG. 3.

FIG. 5 is a top view of an exemplary pre-alignment device that may beused with the first nanotube collection apparatus shown in FIG. 4.

FIG. 6 is an enlarged schematic illustration of an exemplary secondnanotube collection apparatus that may be used with the nanotube meshstructure production system shown in FIG. 3.

FIG. 7 is a top view of an alternative pre-alignment device that may beused with the second nanotube collection apparatus shown in FIG. 6.

DETAILED DESCRIPTION

The implementations described herein relate to systems and methods ofproducing a carbon nanotube mesh structure. In the exemplaryimplementation, the system includes a Langmuir-Blodgett type apparatusincluding a bath of solution having a plurality of nanotubes floating ona surface of the solution. The system also includes conveyor feedsystems that substantially continuously direct a flexible, elongatedsubstrate past the surface of the solution such that the nanotubescouple to the substrate. The nanotubes from a first conveyor feed systemare combined with the nanotubes from a second conveyor feed system toform the nanotube mesh structure. By substantially continuously couplingnanotubes to substrates of the conveyor feed systems, a substantiallycontinuous nanotube mesh structure is formed when the nanotubes arecombined. As such, the system described herein facilitates substantiallycontinuous production of the nanotube mesh structure whose size is onlylimited in one dimension (i.e., a width of the substrate).

Referring to the drawings, implementations of the disclosure may bedescribed in the context of an aircraft manufacturing and service method100 (shown in FIG. 1) and via an aircraft 102 (shown in FIG. 2). Duringpre-production, including specification and design 104 data of aircraft102 may be used during the manufacturing process and other materialsassociated with the airframe may be procured 106. During production,component and subassembly manufacturing 108 and system integration 110of aircraft 102 occurs, prior to aircraft 102 entering its certificationand delivery process 112. Upon successful satisfaction and completion ofairframe certification, aircraft 102 may be placed in service 114. Whilein service by a customer, aircraft 102 is scheduled for periodic,routine, and scheduled maintenance and service 116, including anymodification, reconfiguration, and/or refurbishment, for example. Inalternative implementations, manufacturing and service method 100 may beimplemented via vehicles other than an aircraft.

Each portion and process associated with aircraft manufacturing and/orservice 100 may be performed or completed by a system integrator, athird party, and/or an operator (e.g., a customer). For the purposes ofthis description, a system integrator may include without limitation anynumber of aircraft manufacturers and major-system subcontractors; athird party may include without limitation any number of venders,subcontractors, and suppliers; and an operator may be an airline,leasing company, military entity, service organization, and so on.

As shown in FIG. 2, aircraft 102 produced via method 100 may include anairframe 118 having a plurality of systems 120 and an interior 122.Examples of high-level systems 120 include one or more of a propulsionsystem 124, an electrical system 126, a hydraulic system 128, and/or anenvironmental system 130. Any number of other systems may be included.

Apparatus and methods embodied herein may be employed during any one ormore of the stages of method 100. For example, components orsubassemblies corresponding to component production process 108 may befabricated or manufactured in a manner similar to components orsubassemblies produced while aircraft 102 is in service. Also, one ormore apparatus implementations, method implementations, or a combinationthereof may be utilized during the production stages 108 and 110, forexample, by substantially expediting assembly of, and/or reducing thecost of assembly of aircraft 102. Similarly, one or more of apparatusimplementations, method implementations, or a combination thereof may beutilized while aircraft 102 is being serviced or maintained, forexample, during scheduled maintenance and service 116.

As used herein, the term “aircraft” may include, but is not limited toonly including, airplanes, unmanned aerial vehicles (UAVs), gliders,helicopters, and/or any other object that travels through airspace.Further, in an alternative implementation, the aircraft manufacturingand service method described herein may be used in any manufacturingand/or service operation.

FIG. 3 is a schematic illustration of an exemplary nanotube meshstructure (NMS) production system 200. In the exemplary implementation,NMS production system 200 includes a first nanotube collection apparatus202 and a second nanotube collection apparatus 204. First nanotubecollection apparatus 202 includes a first bath 206 of solution 208 and afirst conveyor feed system 210 operable with first bath 206, and secondnanotube collection apparatus 204 includes a second bath 212 of solution208 and a second conveyor feed system 214 operable with second bath 212.Specifically, first conveyor feed system 210 includes a first collectionroller 216, a first bonding roller 218, a tensioning roller 220, and afirst flexible substrate 222 coupled about rollers 216, 218, and 220.Second conveyor feed system 214 includes a second collection roller 224,a second bonding roller 226, and a second flexible substrate 228 coupledabout rollers 224 and 226.

In the exemplary implementation, first and second collection rollers 216and 224 are positioned adjacent to first and second baths 206 and 212such that first and second substrates 222 and 228 contact respectivebaths 206 and 212 of solution 208. Each bath 206 and 212 includes aplurality of nanotubes 230 floating on a surface 232 of solution 208. Assuch, first and second substrates 222 and 228 collect nanotubes 230 onattachment surfaces 234 thereof as collection rollers 216 and 224 directfirst and second substrates 222 and 228 past surfaces 232 of solution208. Moreover, first and second nanotube collection apparatuses 210 and214 are operable to facilitate substantially aligning nanotubes 230 oneach substrate 222 and 228 in different, substantially parallelorientations. For example, as will be described in more detail below,collection apparatuses 202 and 204 include pre-alignment devices 235that facilitate aligning nanotubes 230 within each bath 206 and 212 ofsolution 208.

Solution 208 may be any solution that enables NMS production system 200to function as described herein. For example, solution 208 is selectedto have sufficient surface tension that enables nanotubes 230 to besubstantially aligned as a surface area (not shown) of surface 232 ismodified. An exemplary solution includes, but is not limited to, anaqueous surfactant solution.

First and second bonding rollers 218 and 226 are positioned downstreamfrom baths 206 and 212 of solution 208 such that first portions 236 offirst and second substrates 222 and 228 have nanotubes 230 collectedthereon. As used herein, “downstream” refers to a direction 238 of NMSproduction flow along each conveyor feed system 210 and 214. Bondingrollers 218 and 226 are positioned adjacent to each other such thatsubstrates 222 and 228 converge to force nanotubes 230 on each substrate222 and 228 into contact at a first interface 240 defined therebetween.As such, nanotubes 230 from each substrate 222 and 228 are used to forma nanotube mesh structure (NMS) 242 being discharged from bondingrollers 218 and 226.

NMS production system 200 also includes a first energy source 244 thatfacilitates joining nanotubes 230 to form NMS 242. Specifically, firstenergy source 244 directs energy 246 towards first interface 240 tothermally couple nanotubes 230 at first interface 240 together. Firstenergy source 244 may be any source of energy that enables NMSproduction system 200 to function as described herein. Exemplary energysources include, but are not limited to, an x-ray energy source, avisible light energy source, an infrared energy source, an ultra-violetenergy source, and/or an electron beam energy source. In an alternativeimplementation, nanotubes 230 are thermally coupled by heating bondingrollers 218 and 226 such that the heat is transferred to nanotubes 230through first and second substrates 222 and 228 at first interface 240.

In the exemplary implementation, NMS production system 200 includes aNMS collection device 248 coupled downstream from first interface 240.Specifically, NMS collection device 248 includes a take-up roller 250coupled, either directly or indirectly, to a second portion 252 of firstsubstrate 222 including NMS 242. Take-up roller 250 presses againstsecond portion 252 to facilitate releasing NMS 242 from first substrate222. As such, take-up roller 250 collects a substantially continuous NMS242 formed at first interface 240 and discharged from bonding rollers218 and 226. Moreover, tensioning roller 220 is coupled downstream fromtake-up roller 250. Tensioning roller 220 ensures first substrate 222remains pressed against take-up roller 250, and ensures first substrate222 remains in tension about rollers 216, 218, and 220.

In some implementations, a second energy source 254 is used to produce amulti-layer nanotube mesh structure (NMS) (not shown). Specifically,second energy source 254 directs energy 246 towards a second interface256 defined between a portion of NMS 242 still coupled to firstsubstrate 222, and a portion of NMS 242 already coupled to take-uproller 250. As such, the number of layers in the multi-layer NMS isselected as a function of rotation of take-up roller 250. Moreover, inone implementation, take-up roller 250 is translateable along its axisof rotation (not shown), which facilitates production of a tubular,multi-layer nanotube mesh structure (not shown). The number of NMSlayers in the tubular, multi-layer nanotube mesh structure is selectedas function of a rotational speed of take-up roller 250 and/or atranslation speed of take-up roller 250 along its axis of rotation. Assuch, the multi-layer NMS may be formed with or without the use energy246 from second energy source 254.

In operation, a first pre-alignment device 237 forces nanotubes 230 infirst bath 206 against attachment surface 234 of first substrate 222. Aswill be described in more detail below, first pre-alignment device 237ensures nanotubes 230 coupled to first substrate 222 are substantiallyaligned in a first orientation (not shown in FIG. 3). First collectionroller 216 then rotates in a first rotational direction 258 to drawnanotubes 230 from solution 208 and to form a first layer 260 ofnanotubes 230 on first substrate 222.

As first nanotube collection apparatus 202 collects nanotubes 230 onfirst substrate 222, second nanotube collection apparatus 204 operatessubstantially simultaneously to collect nanotubes 230 on secondsubstrate 228. Specifically, second collection roller 224 rotates in asecond rotational direction 262 to draw nanotubes 230 from solution 208and to form a second layer 264 of nanotubes 230 on second substrate 228.As will be described in more detail below, second collection roller 224draws nanotubes 230 from second bath 212 at a rate that facilitatessubstantially aligning nanotubes 230 coupled to second substrate in asecond orientation (not shown in FIG. 3). In some implementations, asecond pre-alignment device 239 in second bath 212 facilitatespre-aligning nanotubes 230 in the second orientation before secondcollection roller 224 draws nanotubes 230 from second bath 212.

First and second collection rollers 216 and 224 substantiallycontinuously rotate such that first and second substrates 222 and 228direct layers 260 and 264 of nanotubes 230 towards bonding rollers 218and 226. As first and second layers 260 and 264 reach first interface240, first energy source 244 is activated to direct energy 246 towardsfirst interface 240. In the exemplary implementation, a rate at whichfirst and second layers 260 and 264 are directed towards bonding rollers218 and 226, and/or an intensity of energy 246 are selected to ensurenanotubes 230 from each layer 260 and 264 thermally couple to each otherto form NMS 242. NMS 242 is then directed downstream towards take-uproller 250. More specifically, NMS 242 remains coupled to firstsubstrate 222, and second portion 266 of second substrate 228 releasesNMS 242 and is substantially free of nanotubes 230. Second portion 266of second substrate 228 is then redirected towards second bath 212 toenable additional nanotubes 230 to be collected on second substrate 228.

In some implementations, first and second substrates 222 and 228 arefabricated from different materials to enable NMS 242 to remain coupledto first substrate 222, and to enable NMS 242 to be released from secondsubstrate 228. Alternatively, first and/or second substrates 222 and 228have a surface treatment or have a different surface roughness such thatNMS 242 adheres better to first substrate 222 than to second substrate228.

As described above, take-up roller 250 presses against first substrate222 and/or NMS 242 coupled to first substrate 222 to collect asubstantially continuous NMS 242 thereon. Specifically, NMS 242 couplesto take-up roller 250, and take-up roller 250 rotates in secondrotational direction 262 to facilitate uncoupling NMS 242 from firstsubstrate 222. A third portion 268 of first substrate 222 is thenredirected towards first bath 206 to enable additional nanotubes 230 tobe collected on first substrate 222. As such, first and secondsubstrates 222 and 228 are fabricated from any resilient materialcapable of substantially continuous use in NMS production system 200. Inan alternative implementation, first and second substrates 222 and 228are fabricated from a disposable and/or single use material.

FIG. 4 is an enlarged schematic illustration of first nanotubecollection apparatus 202, and FIG. 5 is a top view of firstpre-alignment device 237. In the exemplary implementation, firstpre-alignment device 237 includes a moveable arm 270 at least partiallysubmerged in first bath 206 of solution 208. Specifically, moveable arm270 extends at least partially below surface 232 of solution 208 toenable moveable arm 270 to substantially align nanotubes 230 floating onsurface 232 in a first orientation 272 against first substrate 222. Forexample, moveable arm 270 translates towards first substrate 222, whichcauses nanotubes 230 to align in a substantially parallel orientationrelative to each other.

Moreover, first orientation 272 is defined by nanotubes 230 extendingtransversely relative to a direction 274 of solution 208 being drawnfrom first bath 206 by first substrate 222. Specifically, attachmentsurface 234 of first substrate 222 is directed past surface 232 withinfirst bath 206 at a rate that forms a velocity gradient 276 withinsolution 208. As such, a film 278 of solution 208 including nanotubes230 substantially aligned in first orientation 272 is drawn from firstbath 206 and coupled to attachment surface 234 of first substrate 222.

FIG. 6 is an enlarged schematic illustration of second nanotubecollection apparatus 204, and FIG. 7 is a top view of secondpre-alignment device 239 that may be used with second nanotubecollection apparatus 204. In the exemplary implementation, rotation ofsecond substrate 228 and/or second collection roller 224 in secondrotational direction 262 causes nanotubes 230 floating on surface 232 ofsecond bath 212 to substantially align in a second orientation 280.Second orientation 280 is defined by nanotubes 230 extendingsubstantially parallel relative to direction 274 of solution 208 beingdrawn from second bath 212 by second substrate 228. Specifically,attachment surface 234 of second substrate 228 is directed past surface232 within second bath 212 at a rate that forms velocity gradient 276within solution 208. As such, film 278 of solution 208 includingnanotubes 230 substantially aligned in second orientation 280, andaligned substantially parallel to each other, is drawn from second bath212 and coupled to attachment surface 234 of second substrate 228.

Referring to FIG. 7, in some implementations, second pre-alignmentdevice 239 facilitates pre-aligning nanotubes 230 in second orientation280 before being drawn from second bath 212 by second substrate 228.Specifically, second pre-alignment device 239 includes a pair ofmoveable arms 271 that extend at least partially below surface 232 ofsolution 208 to enable moveable arms 271 to substantially alignnanotubes 230 floating on surface 232 in second orientation 280. Forexample, moveable arms 271 translate towards each other, which causesnanotubes 230 to align in a substantially parallel orientation relativeto each other.

The implementations described herein relate to a nanotube mesh structureproduction system having a larger production capacity than other knownsystems. The system includes first and second nanotube collectionapparatuses that operate substantially simultaneously to collectnanotubes in differing orientations, and to combine the nanotubes toform the nanotube mesh structure. Each nanotube collection apparatusalso operates substantially continuously to enable a substantiallycontinuous nanotube mesh structure to be formed. Moreover, the systemincludes a nanotube mesh structure collection device that facilitatesforming a multi-layer nanotube mesh structure from the substantiallycontinuous mesh structure. As such, the systems and methods describedherein facilitate efficient production of nanotube mesh structures thatmay be implemented in various practical applications.

This written description uses examples to disclose variousimplementations, including the best mode, and also to enable any personskilled in the art to practice the various implementations, includingmaking and using any devices or systems and performing any incorporatedmethods. The patentable scope of the disclosure is defined by theclaims, and may include other examples that occur to those skilled inthe art. Such other examples are intended to be within the scope of theclaims if they have structural elements that do not differ from theliteral language of the claims, or if they include equivalent structuralelements with insubstantial differences from the literal language of theclaims.

1-14. (canceled)
 15. A method of forming a nanotube mesh structure, saidmethod comprising: continuously directing a first substrate including afirst attachment surface past a surface of a first bath of solutionincluding a plurality of nanotubes floating on the surface of thesolution such that the plurality of nanotubes couple to the firstattachment surface in a first orientation; combining the plurality ofnanotubes in the first orientation with a plurality of nanotubes in asecond orientation, the pluralities of nanotubes combined at aninterface defined therebetween; and thermally coupling the pluralitiesof nanotubes at the interface to form the nanotube mesh structure. 16.The method in accordance with claim 15 further comprising pre-aligningthe plurality of nanotubes in the first bath of solution in the firstorientation prior to being coupled to the first attachment surface. 17.The method in accordance with claim 16, wherein pre-aligning theplurality of nanotubes comprises translating a moveable arm towards thefirst substrate to align the plurality of nanotubes in a substantiallyparallel orientation relative to each other.
 18. The method inaccordance with claim 15, wherein continuously directing a firstsubstrate comprises coupling the first substrate to at least one roller,wherein the first substrate is continuously directed past the surface ofthe solution as the at least one roller rotates.
 19. The method inaccordance with claim 15 further comprising continuously directing asecond substrate including a second attachment surface past a surface ofa second bath of solution including a plurality of nanotubes floating onthe surface of the second bath of solution, the second substrate pastthe surface of the solution at a rate that causes the plurality ofnanotubes in the second bath of solution to substantially align in adirection of the solution being drawn from the bath.
 20. The method inaccordance with claim 19 further comprising pre-aligning the pluralityof nanotubes in the second bath of solution in the second orientationprior to being coupled to the second attachment surface.
 21. The methodin accordance with claim 20, wherein pre-aligning the plurality ofnanotubes in the second bath of solution comprises translating a pair ofmoveable arms towards each other to align the plurality of nanotubes ina substantially parallel orientation relative to each other.
 22. Themethod in accordance with claim 15, wherein thermally coupling thepluralities of nanotubes comprises directing energy towards thepluralities of nanotubes at the interface.
 23. The method in accordancewith claim 15 further comprising redirecting a portion of the firstsubstrate substantially free of nanotubes towards the bath of solution.24. The method in accordance with claim 19, further comprising directingthe first substrate and directing the second substrate substantiallysimultaneously.
 25. The method in accordance with claim 19, whereinthermally coupling the pluralities of nanotubes at the interfacecomprises transferring heat to the pluralities of nanotubes through thefirst substrate.